A.F. van Leeuwenhttp://repub.eur.nl/ppl/27582/
List of Publicationsenhttp://repub.eur.nl/eur_signature.pnghttp://repub.eur.nl/
RePub, Erasmus University RepositoryBinocular eye movements in humans: from optimal binocularity to strabismushttp://repub.eur.nl/pub/22238/
Wed, 26 Jun 2002 00:00:01 GMT<div>A.F. van Leeuwen</div>
Binocular vision and stereopsis is one of the major characteristics of frontal eyed
species, such as humans. Binocular vision results from the projection of 3D-objects
on corresponding area's of the retina's of the two eyes. An individual with. binocular
vision perceives one single image of the object containing depth information (binocular
vision). The minute differences between the' left and the right image (disparity) ideally
give rise to stereoscopic vision. This entity of the binocular system has been used for
artificial stereopsis in 3-D pictures and movies.
The importance of binocular vision in daily life becomes clear when individuals
with optimal binocular coordination are forced to use mostly one eye (e.g. because
of an eye infection). Their loss of binocular visual information causes difficulties with
simple tasks, like shaking hands. Individuals who have sub-optimal binocularity for a
longer period can function very well due to adaptive mechanisms and the use of nonstereoscopic
depth cues. Many people are unaware of their slight sub-optimal binocularity
which only a stereopsis test reveals. People with low vision in one of their eyes,
have less binocularity but the use of both eyes can still be very useful for the detection
of large moving objects such as approaching cars. They usually have no impairments in
their daily tasks. Individuals with vision in one eye only adapt mainly by making more
head movements. With this adaptation they have no difficulties, even with tasks like
driving a car.Saccadic binocular coordination in alternating exotropiahttp://repub.eur.nl/pub/61017/
Mon, 10 Dec 2001 00:00:01 GMT<div>A.F. van Leeuwen</div><div>H. Collewijn</div><div>J.T.H.N. de Faber</div><div>J. van der Steen</div>
We studied the coordination of binocular eye movements in human subjects with alternating exotropia (divergent strabismus). Binocular saccades were recorded in six subjects during binocular and monocular viewing. Subjects were instructed to make saccades between two continuously lit targets (LED's) presented in an isovergence array (with the straight-ahead target 130 cm from the eyes) in a dimly lit room. For saccades up to 20° amplitude, there were no large differences in the dynamics of the saccades between control and exotropic subjects. However, for larger amplitudes subjects frequently alternated the eye of fixation during saccades. That is, subjects fixated the left target with the left eye and the right target with the right eye. The alternation in eye fixation at the end of the saccade was taken into account in the programming of the saccades. The amplitudes of the alternating saccades were approximately equal to the target amplitude minus the strabismus angle. We conclude that for those saccades where alternation occurs, there is not only a change in the eye of fixation, but also a change in the target representation provided by either eye. Thus, in this group of strabismic patients, saccades may be programmed in a retina-centered coordinate system, if we assume that for making a saccade to a new target in the contralateral visual field its representation on the temporal retinal field of the currently fixating eye is suppressed and the retinotopic target information is derived from the non-fixating eye. In executing the saccade, the non-fixating eye automatically becomes the fixating eye.Gaze-shift dynamics in subjects with and without symptoms of convergence insufficiency: Influence of monocular preference and the effect of traininghttp://repub.eur.nl/pub/62807/
Wed, 01 Sep 1999 00:00:01 GMT<div>A.F. van Leeuwen</div><div>M.J. Westen</div><div>J. van der Steen</div><div>J.T.H.N. de Faber</div><div>H. Collewijn</div>
Dynamics of horizontal vergence movements: Interaction with horizontal and vertical saccades and relation with monocular preferenceshttp://repub.eur.nl/pub/61205/
Tue, 01 Dec 1998 00:00:01 GMT<div>A.F. van Leeuwen</div><div>H. Collewijn</div><div>D.W. Erkelens</div>
Binocular saccidic eye movements in multiple sclerosishttp://repub.eur.nl/pub/62806/
Thu, 01 May 1997 00:00:01 GMT<div>J.P. Flipse</div><div>C.S.M. Straathof</div><div>J. van der Steen</div><div>A.F. van Leeuwen</div><div>P.A. van Doorn</div><div>F.G.A. van der Meché</div><div>H. Collewijn</div>